Freezeproof expansion valve



July 20, 1954 METTLER FREEZEPROOF EXPANSION VALVE Filed Oct. 25, 1951 EVAPORATUR Fig.4-

eorge NeH/er LIQUID REC.

COMPRESSOR INVENTOR.

CONDENSER Patented July 20, 1954 FREEZEPROOF EXPANSION VALVE George Mettler, Union City, N. 3., assignor of one-third to 'Magnus Bjorndal, Weehawken,

Application October 25, 1951, Serial No. 253,121

3 Claims. 1;

This invention relates to improvements in expansion valves for use in refrigeration and air conditioning systems, and specifically it refers to improved freeze proof, moisture separating expansion valves, which may be used instead of the so called capillary tubes widely used in commercial installations.

This invention is .an improvement over my Patent Number 2,534,874 issued on December 19, 1950.

Expansion valves and capillaries have one difficulty in common, namely that if any moisture is present in the system, this will freeze up at the point where expansion takes place and will eventually clog up the valve or capillary. This can cause a great deal of costly service Work and may also cause the spoilage of food products stored. As stated in my patent mention supra, the freezing up of expansion valves can be eliminated by the use of a moisture separator, such as there described. This however, requires an expensive valve and I have therefore, improved my moisture separator so that I can dispense with the valve.

The present invention therefore, is a device which combines a simplified valve with features of my previous moisture separator, thereby mak ing it possible to eliminate capillary tubes as well as more expensive valves. This combined valve and the moisture separator eliminates all the difficulties mentioned above, and presents a unit of low cost, high efficiency and long lasting quality.

The object of my invention is to provide a freeze proof expansion valve for the use in refrigeration and air conditioning systems.

Another object of my invention is to provide a combined expansion valve and moisture separator which can be used instead of capillary tubes.

Still another object of my invention is to provide a freeze proof expansion valve Which can be manufactured at low cost.

Other objects and advantages of my invention will be apparent from the following description and claims.

In the accompanying drawing, forming a part of this specification, and in which like numerals are employed to designate like parts throughout,

Figure 1 is a front view of a freeze proof expansion valve embodying my invention,

Figure 2 is a longitudinal partial section of the valve shown in Figure 1,

Figure 3 is a section taken along line 33 in Figure 2,

Figure 4 represents a section taken along line 4-4 in Figure 2,

Figure 5 represents a schematic diagram of a refrigeration system using my device, and,

Figure 6 represents a greatly enlarged part of the section shown in Figure l.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of my invention, the numeral l8 designates the outer tubular body of my valve. The tubular body It, has a standard pipe fitting II, at one end and a pipe fitting l2, at the other end. These fittings may be preferably soldered to the tube H], but other methods of connecting the pipe joints are optional. The fitting H, has an opening |3, which leads through a strainer It, to the inner space inside of tube Ill. The fitting l2, has an opening it, at the outer end. The inside of the central opening l5, in the fitting I2, is tapped with a thread and the valve unit proper is designated by numeral It.

The valve unit it, has a central bore H, at one end, which when screwed into fitting l2, communicates with the central hole It: in same. The central bore I l, extends to about the middle of the unit It, Where it terminates in a transverse hole l8. Instead of a single hole, this may also be a plurality of holes. The unit I6, has screw threads along its entire outer surface of the body part, which is of slightly larger diameter than the threaded shank I9, which is screwed into fitting l2. The threaded body part is tapered slightly toward both ends and is completely covered by a flexible tubing 20, which is preferably made from neoprene or silicone rubber. A helical wire spring 2| is placed over the tubing 21!. The spring 2|, is wound opposite to the screw thread on the body portion of the valve I5.

An enlarged view illustrated in Figure 6, shows how the rubber tubing 20, is held tightly over the threaded portion of the valve body IS with the inside of said tubing 2!], pressing hard against the outer periphery of the screw threads on body l6. As mentioned above, the helical spring 2|, is wound in the opposite direction from the screw thread on it, thereby preventing that the wires of the spring 2|, may fall into the grooves formed by the threads and thus closing same. This is important in the proper operation of the unit, inasmuch as the screw threads act as a needling device or capillary tube letting through a certain amount of refrigerant.

In Figure 5, is schematically illustrated how the present invention fits into a refrigeration system. The usual refrigeration systems consists of a liquid receiver from which the liquified refrigerant passes through the expansion valve IE, to the evaporator where it is evaporated into the gas state. The evaporated gas is compressed in a compressor and passed through the condenser where it again turns into liquid form. The expansion valve [6, may be placed at any point between the liquid receiver and the evaporator as illustrated.

The operation of my invention is as follows: when the unit is placed in the system as illustrated in Figure 5, with the pipe fittings II and 12 connected into the pipe connection from the liquid receiver to the evaporator, the liquid refrigerant enters through the opening I5, in fitting l2, and continues in through the central bore I! to the transverse hole l8, whereupon a certain amount of the liquid refrigerant will pass through the capillary tubes formed by the screw thread on the body of valve [6, as described supra. With excess pressure the refrigerant will expand the rubber tube 29, and the spring 2|, and will pass over the screw threads. The refrigerant will now escape from both ends of the rubber tube 20, and will expand into the chamber formed inside of tube Ill. The refrigerant will now be partly gas and partly liquid in the chamber formed by tube It, and will escape through strainer l4, and pening l3, into the pipe leading to the evaporator, where complete evaporation will take place. If any moisture is present in the refrigerant, this will freeze as the gas expands under the rubber tubing 29, and will form a small amount of ice here. This ice will only expand the tubing 20, but will not block the continuous passage of gas and liquid refrigerant through the screw threads and also under the ice or under the rubber tubing. After the refrigeration cycle has progressed a few times, all the moisture is frozen to ice and is collected under the rubber tube 20. The ice will remain here and will not affect the operation of the system until the same is stopped. It is then possible to take out the valve 16 and dry out same or replace it with a new one. In this manner, a system can be completely dried out and can also be kept operating for long periods of time with a slight amount of moisture without trouble.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred embodiment of the same and that various changes in the shape, size and arrangement of parts, may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. A freeze proof expansion valve of the character described comprising a tubular housing having a central passage; a fitting fastened to said housing at one end; a strainer fastened in the central passage in said fitting; a second fitting fastened in the other end of said housing; a valve element placed inside of said housing and having a threaded shank screwed into said second fitting, said valve element comprising a threaded body having a central bore from said shank end,

said centrol bore terminating in a transverse hole in the middle of said body; a flexible tube placed over said body in pressure contact with said threaded portion, and a helical spring wound over said flexible tube in the oposite direction of said screw thread.

2. A freeze proof expansion valve of the character described comprising a tubular housing having a central passage; a fitting fastened to said housing at one end; a strainer fastened in the central passage in said fitting; a second fitting fastened in the other end of said housing, said second fitting having an inlet opening leading to a tapped hole in the inner end; a valve element placed inside of said housing, said element having a threaded shank at one end screwed into said tapped hole in said second fitting; said valve element comprising a threaded body portion having a central bore from said shank end; said central bore terminating in a plurality of transverse holes communicating with the outside threaded body portion of said element, said transverse holes being located in the middle of said body; a resilient tube placed over said threaded body in pressure contact with said threads, and a helical spring wound over said flexible tube in the opposite direction of said screw threads.

3. A freeze proof expansion valve as described in claim 2 in which said valve element is tapered slightly toward both ends.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 384,306 Bourdil June 12, 1888 2,289,905 Dasher July 14, 1942 2,375,646 Gross May 8, 1945 

